CN112665519B - Device and method for measuring radial deformation by laser - Google Patents

Abstract

A device and method for measuring radial deformation by laser is used for the measurement of radial deformation in uniaxial experiments, which can effectively solve the problems of large errors, many influencing factors and inability to obtain radial deformation in real time in the existing radial deformation measuring device. of insufficiency. The device includes a fixed plate 1 , a splint 2 , a laser transmitter 3 , an outer reflection ring 4 , and an inner reflection ring 5 . Simple installation, accurate and real-time measurement of radial deformation.

Description

Device and method for measuring radial deformation by laser

technical field

The invention belongs to the technical field of geotechnical testing, and relates to a device and a method for measuring radial deformation by using a laser.

Background technique

In the geotechnical test, measuring the radial deformation of the test block to obtain the Poisson's ratio is the premise of other researches. At present, the main methods of measuring the radial deformation of the test block are the fixed local displacement sensor and the method of attaching strain gauges. These methods have large measurement errors and are greatly affected by the operation of the experimenter, and cannot measure the large deformation well. radial deformation. And with the popularization of dynamics research, the relationship between radial deformation and time also needs to be explored urgently. Therefore, it is very important to develop a device and method that can measure radial deformation in real time and accurately.

SUMMARY OF THE INVENTION

In order to overcome the shortcomings of the existing radial deformation measuring device, such as large errors, many affected factors and inability to obtain radial deformation in real time, the present invention provides a device and method for measuring radial deformation by laser, which can measure accurately and in real time. radial deformation.

The technical scheme adopted by the present invention to solve its problem is:

A device for measuring radial deformation by laser, which can measure radial deformation accurately and in real time, and is used for the measurement of radial deformation in uniaxial experiments. Ring 4, inner reflection ring 5. The laser transmitter 3 and the outer reflection ring 4 are fixed on the fixing plate 1 through the clamping plate 2 .

A method for measuring radial deformation by laser includes the following steps:

The first step is to assemble the measuring device, put the inner reflection ring 5 on the test block 7, and adjust the height of the fixing plate 1 so that the outer reflection ring 4 and the inner reflection ring 5 are approximately at the same level.

The second step is to measure the distance d between the inner reflection ring 5 and the outer reflection ring 4 and the radius R of the test block.

The third step is to turn on the laser transmitter 3 , there are equally spaced light spots on the outer reflection ring 4 , select a point N ₁ that is far from the laser transmitter 3 , record its position and the light between the point and the laser transmitter 3 The number of points N.

The fourth step, through the known laser incident angle θ (very small), calculate the angle φ between the two adjacent light spots on the outer reflection ring ₄ and the center of the test block, the arc length S and the total arc to the N1 point. long S ₁ . Calculated as follows:

S ₁ =NS

The fifth step is to perform a uniaxial experiment. As the experiment proceeds, the light spot _on the outer reflection ring moves continuously, and the distance ΔS moved by the N1 point is recorded.

弧长

以及到新N₁点的总弧长S₂。计算公式如下：The sixth step is to calculate the angle between the two adjacent light spots on the outer reflection ring 4 after deformation and the center of the test block

arc length

and the total arc length S ₂ to the new N ₁ point. Calculated as follows:

_The seventh step is to calculate the radial deformation ΔR by measuring the distance ΔS moved by the N1 point. Calculated as follows:

The beneficial effects of the invention are as follows: the assembly is simple, and is less affected by the operation of the experimenter; the radial deformation of the test block can be measured accurately and in real time.

Description of drawings

Below in conjunction with accompanying drawing and embodiment, the present invention is further described:

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is the derivation schematic diagram of undeformed formula of the present invention;

Fig. 3 is the formula derivation schematic diagram after deformation of the present invention;

Figure 4 is a diagram of a three-dimensional device of the present invention.

In the figure 1. Fixed plate, 2. Plywood, 3. Laser transmitter, 4. External reflection ring, 5. Internal reflection ring, 6. Light, 7. Test block.

Detailed ways

In FIG. 1 , the laser transmitter 3 and the outer reflection ring 4 are fixed on the fixing plate 1 through the clamp plate 2 , the laser transmitter 3 emits laser light at a small incident angle, and the inner reflection ring 5 and the outer reflection ring 4 are repeatedly Reflection, many photoelectrics are formed on the two reflecting plates (the arc lengths between the two light spots are equal), and a plurality of light rays 6 are formed between the two plates.

In FIG. 1, since the radius of the inner reflection ring 5 is changed, the reflection angle is changed, and the spot position of the reflected light 6 on the outer reflection plate is also changed accordingly. The radius of the inner reflection ring 5 becomes larger, and the reflection angle becomes smaller. The arc length between two adjacent light spots decreases.

In FIG. 4 , the inner reflection ring 5 is sleeved on the test block 7 . During the uniaxial experiment, the radial deformation of the test block 7 drives the radial deformation of the inner reflection ring 5 .

Claims (1)

1. A method for measuring radial deformation by laser, the method uses a device for measuring radial deformation by laser, and the device comprises a fixed plate (1), a splint (2), a laser transmitter (3), an external reflection The ring (4), the inner reflection ring (5), and the laser transmitter (3) are arranged on the outer reflection ring (4), and the outer reflection ring (4) is fixed on the fixing plate (1) through the splint (2); The method includes the following steps: The first step is to assemble the measuring device, put the inner reflection ring (5) on the test block (7), and adjust the height of the fixing plate (1) so that the outer reflection ring (4) and the inner reflection ring (5) are roughly in the same position horizontal height; The second step is to measure the distance d between the inner reflection ring (5) and the outer reflection ring (4) and the radius R of the test block; The third step is to turn on the laser transmitter (3), light spots with equal spacing appear on the outer reflection ring (4), select a point N ₁ farther from the laser transmitter (3), record its position and the relationship between this point and the laser emission The number of light spots N between the devices (3); The fourth step is to calculate the angle φ between the two adjacent light spots on the outer reflection ring ( ₄ ) and the center of the test block, the arc length S, and the total arc length S to the N1 point through the known laser incident angle θ. ₁ ; the calculation formula is as follows:

S ₁ =NS; The fifth step is to carry out a uniaxial experiment. As the experiment proceeds, the light spot on the outer reflection ring moves continuously, and the distance ΔS moved by the N1 point is recorded _; The sixth step is to calculate the angle between the two adjacent light spots on the outer reflection ring (4) after deformation and the center of the test block

arc length

And the total arc length S ₂ to the new N ₁ point, the calculation formula is as follows:

The seventh step is to calculate the radial deformation ΔR by measuring the distance ΔS moved by the N1 point _; the calculation formula is as follows:

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